Dual-Channel Phosphorescence Ratiometry and Phosphorescence Lifetime Imaging of Mitochondria-Specific Methionine Sulfoxide Reductase Activity
Xuewei Wang, Chen Chen, Yang Tian, Qi‐Wei Zhang
Abstract
Methionine sulfoxide reductases (Msrs) are essential for preserving redox homeostasis in the nervous system, with dysregulation implicated in Alzheimer's disease (AD). Conventional fluorescence-based assays for Msrs activity sensing are hampered by background interference, limited sensitivity, and inadequate quantification. This work introduces a novel supramolecular probe exhibiting redox-responsive dual-channel room-temperature phosphorescence (RTP) in aqueous media on a microsecond time scale. Upon reduction by Msrs, the probe transitions from its oxidized to reduced state, manifested by a red-shifted phosphorescence emission and extended lifetime in the microsecond range, which enables precise quantification of mitochondria-targeted Msrs activity via phosphorescence ratiometry and phosphorescence lifetime imaging (PLIM). The probe's utility is demonstrated in visualizing neuronal Msrs activity and distribution within the mouse brain, which reveals a marked downregulation of Msrs activity in an AD model, highlighting the probe's potential in elucidating redox-related pathological mechanisms underlying neurodegenerative disorders.